Apache Hadoop 2.9.1 Release Notes

These release notes cover new developer and user-facing incompatibilities, important issues, features, and major improvements.


Aliyun OSS is widely used among China’s cloud users and this work implemented a new Hadoop compatible filesystem AliyunOSSFileSystem with oss scheme, similar to the s3a and azure support.


Aliyun OSS is widely used among China’s cloud users and this work implemented a new Hadoop compatible filesystem AliyunOSSFileSystem with oss:// scheme, similar to the s3a and azure support.


This JIRA makes following change: Change Router metrics context from ‘router’ to ‘dfs’.


Mount tables support ACL, The users won’t be able to modify their own entries (we are assuming these old (no-permissions before) mount table with owner:superuser, group:supergroup, permission:755 as the default permissions). The fix way is login as superuser to modify these mount table entries.


Ensure only NM classpath in 2.x gets TSv2 related hbase jars, not the user classpath.


[WASB] Fix Azure implementation of Filesystem.rename to ensure that at most one operation succeeds when there are multiple, concurrent rename operations targeting the same destination file.


Support multi-thread pre-read in AliyunOSSInputStream to improve the sequential read performance from Hadoop to Aliyun OSS.


Fix the document error of setting up HFDS Router Federation


Change default State Store from local file to ZooKeeper. This will require additional zk address to be configured.